Polyetherimide resins are high temperature engineering plastics that exhibit good thermal stability and typically do not require stabilizing additives. However, under certain extreme conditions, such as, for example, when molding unusually large parts or when operating at the upper extreme of the recommended molding temperature or residence time, undesirable changes in the polyetherimide resin, such as, for example, increased viscosity, increased yellowness and contamination of the polyetherimide resin with "black specks", may occur. The black speck contamination is thought to be the result of localized thermal degradation and carbonization of the polyetherimide resin due to overheating.
A polyetherimide resin that exhibits improved melt stability and resistant to degradation under extreme processing conditions is desired.